JPH0961687A - Lens holding device and optical equipment using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and easily position and assemble a plastic lens in a lens barrel in an optical axis direction and a direction orthogonal to an optical axis by dividing a lens holding member into at least two by a cross section parallel with the optical axis and arranging a positioning part near the cross section. SOLUTION: The plastic lens 1, a frange part 2 and the positioning part 3 constitute one element of a plastic member PL. LX is the lens holding member and has a 1st holding member 4 and a 2nd holding member 5 holding the plastic member PL. Engaging parts 6 to 9 engaged with the positioning part 3 provided at the calyx part 2 are provided on the 1st and the 2nd holding members 4 and 5. The holding members 4 and 5 perform the positioning of the lens 1 in a radial direction and the optical axis direciton by holding projecting parts 3a and 3b between recessed parts 6 and 7 and recessed parts 8 and 9, respectively, and interposing the frange part 2 between the holding members 4 and 5 in the optical direction without a gap.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic lens holding device in a lens unit using a lens and an optical apparatus using the same, and more particularly to positioning and optical in the optical axis direction when holding a plastic lens in a lens barrel. It is suitable for optical equipment such as still cameras and video cameras in which positioning in the direction orthogonal to the axis (radial direction) is performed accurately without impairing optical performance.

[0002]

2. Description of the Related Art Conventionally, plastic lenses are often used together with camera lenses in photographing lenses of still cameras and video cameras. This plastic lens is characterized by being inexpensive and lightweight. When a plastic lens is used as part of a shooting lens, the plastic lens has a higher coefficient of thermal expansion than a glass lens (glass lens), and does not lead to lens eccentricity or lens surface deformation due to expansion or contraction due to temperature changes. It becomes important to do so.

Conventionally, a plastic lens is provided with a convex portion on a flange portion, and the convex portion is fitted into a concave portion of a lens holding member such as a gap ring to determine a radial position of the lens. We have proposed a plastic lens holding device that prevents the stress due to lens expansion / contraction from being applied directly to the effective surface of the lens.

[0004]

The plastic lens holding device proposed in the prior art described above holds a plastic lens, such as a gap ring, by a member that sandwiches the plastic lens in the direction of the optical axis. There is a problem in that it is difficult to assemble because the convex portion and the concave portion have a positional relationship that is not visible to the operator.

According to the present invention, a lens, for example, a plastic lens can be accurately and easily positioned and assembled in the lens barrel (in the lens unit) in the optical axis direction and the direction orthogonal to the optical axis (radial direction). An object of the present invention is to provide a lens holding device that does not impair the optical performance even if the environmental temperature changes and an optical device using the same.

[0006]

The lens holding device of the present invention comprises: (1-1) A flange portion for positioning in the optical axis direction is provided on the peripheral portion of the lens, and the flange portion is used for radial positioning of the lens. When the lens holding member provided with the positioning portion is held by the lens holding member having the engaging portion that engages with the positioning portion, the lens holding member has at least 2 by a cross section substantially parallel to the optical axis.
It is characterized in that it is divided into two holding members, and the positioning portion is positioned near the cross section.

In particular, (1-1-1) the positioning portion and the engaging portion are engaged in the relationship of a convex portion and a concave portion, (1
-1-2) The positioning portion is provided on at least two positions on a straight line including the center of the lens, with the center sandwiched therebetween, and radial distances from the center being substantially equal to each other.
-3) A plurality of the positioning portions are provided, and the plurality of positioning portions are provided so as to deviate from point symmetry in the cross section, (1-1-4) The lens is a plastic lens, etc. Is characterized by.

The optical device of the present invention has a constitutional requirement (1-1).
The image forming device is characterized in that an image is formed on a predetermined surface by using a taking lens housing the lens holding device.

[0009]

1 (A) and 1 (B) are a sectional view and a plan view of a main portion of a first embodiment of the present invention. FIG. 2 is a side view of a main part of the first embodiment of the present invention. FIG. 3 is an explanatory view when a lens according to the present invention, for example, a plastic lens member is held by a lens holding member, and FIG. 4 is a schematic rear view of FIG. 3 when a plastic member is held by the lens holding member.

In each figure, reference numeral 1 designates a lens, for example a plastic lens, in which the front and back lens surfaces have different radii of curvature. Reference numeral 2 denotes a collar portion having a predetermined thickness, which is provided in the peripheral portion of the plastic lens 1 and determines the position of the plastic lens 1 in the optical axis direction. 3a, 3b
(3) is a positioning part. The positioning portions 3 are symmetrically arranged on the front and back sides of the collar portion 2, and the first convex portions 3a (3a1, 3a2) and the collar portion 2 which determine the radial position of the plastic lens 1 are provided.
Only on the front side of the optical axis of the plastic lens 1
The second convex portion 3b is arranged so that the distance from a is equal to that of the convex portion 3a, and determines the radial position of the plastic lens 1.

The plastic lens 1, the flange portion 2 and the positioning portion 3 constitute one element of the plastic lens member PL. LX is a lens holding member, and has a first holding member 4 that holds the plastic lens member PL and a second holding member 5 that holds the plastic lens member PL. The first holding member 4 and the second holding member 5 each have an engaging portion (6) that engages with the positioning portion 3 provided on the collar portion 2.
~ 9) are provided.

The first holding member 4 is a first engaging portion for sandwiching the convex portions 3a (3a1, 3a2) provided on the collar portion 2.
A second concave portion 9 is provided as an engaging portion for sandwiching the concave portion 6 and the convex portion 3b. The second holding member 5 has a third concave portion 7 as an engaging portion for sandwiching the convex portions 3a (3a1, 3a2) provided on the collar portion 2 and a fourth concave portion 8 as an engaging portion for sandwiching the convex portion 3b. Is provided.

In this embodiment, the holding members 4 and 5 have a slight gap in the radial direction when assembled as shown in FIG. 3, but the convex portions 3a are formed into the concave portions 6 and the concave portions 7 and the convex portions 3b. It is sandwiched by the recesses 8 and 9, respectively, and acts to determine the radial position of the plastic lens 1. Further, at this time, the collar portion 2 has its thickness appropriately set and is sandwiched in the optical axis direction with respect to the holding members 4 and 5 without any gap. This positions the plastic lens 1 in the optical axis direction.

In this embodiment, the lens holding member LX is composed of two holding members 4 and 5, but it may be divided into three or more parts in a section parallel to the optical axis 1a.

In this embodiment, a gap is formed in the radial direction when the plastic lens 1 is held by the holding members 4 and 5. As a result, when the plastic lens 1 expands or contracts due to temperature change or the like, the stress due to the radial expansion or contraction of the lens is applied to the convex portions 3a and 3a.
b so that each convex portion (3a, 3b) and the collar portion 2
The curved surface of the plastic lens 1 is prevented from being deformed by the deformation of the. Further, the convex portions 3a and 3b are arranged so that the distance from the optical axis center 1a of the lens is the same, so that even if the convex portion 3a and 3b are subjected to the deformation, decentering of the lens is avoided.

In this embodiment, the plastic lens 1 can be inserted into the holding member 4 or the holding member 5 while visually observing the assembly procedure. As a result, the convex portions 3a and 3b and the concave portions (6 to 9) can be easily fitted into each other. Also, when the insertion direction of the plastic lens 1 having the lens surfaces having different curvatures on the front and back surfaces is incorrect, the projection 3b and the recesses 8 and 9 corresponding thereto cannot be fitted because they are arranged only on the front side. In this way, incorrect insertion is prevented.

FIG. 5 and FIG. 6 are a plan view and a side view of an essential part of Embodiment 2 of the present invention, respectively.

In FIGS. 5 and 6, 12 (12a, 12
Reference numeral b) is a second convex portion as a positioning portion, which is provided on each of the front and back surfaces of the collar portion 2. Reference numeral 11 denotes a second concave portion 10 provided as an engaging portion on the first member 4, and reference numeral 10 denotes a fourth concave portion provided on the second holding member 5 as an engaging portion. The positioning portion 12 and the engaging portions 10 and 11 are engaged with each other in the relationship of a convex portion and a concave portion.
The respective configurations of the collar portion 2, the convex portion 3a, and the holding members 4 and 5 and their relationships are the same as those in the first embodiment shown in FIG.

In this embodiment, the positioning portion 12 determines the radial position of the plastic lens 1, has a shape different from that of the first convex portion 3a, and is symmetrical with respect to the front and back of the collar portion 2. Are doing

In this embodiment, reference numerals 11 and 12 are third and fourth concave portions which are respectively arranged on the holding members 4 and 5 and which sandwich the convex portion 12 therebetween. In this embodiment, when the plastic lens 1 expands or contracts due to a temperature change or the like, the stress is applied to the convex portions 3 a and the convex portions 12. Further, the convex portions 3a and the convex portions 12 are arranged symmetrically on the front and back of the collar portion 2, respectively. As a result, the stresses applied to the protrusions 3a and 12 are made equal to each other, and the stress in the twisting direction on the collar 2 is completely prevented.

7 (A) and 7 (B) are sectional views and plan views of essential parts of Embodiment 3 of the present invention, and FIG. 8 is a side view of the essential parts of Embodiment 3 of the present invention. In this embodiment, three concave portions 13 and 1 are provided as positioning portions on the flange portion 2 around the plastic lens 1.
4, 15 are provided. The first and second holding members 4 and 5 are provided with three recesses 13, 14, 15 provided in the collar portion 2.
Three convex portions 16, 17, 18 as engaging portions corresponding to
Is provided. The positioning portions 13, 14, 15 are engaged with the engaging portions 16, 17, 18 to hold the plastic lens 1 on the holding members 4, 5. As a result, like the first and second embodiments, the decentering of the lens is prevented and the erroneous insertion before and after the optical axis is prevented.

In the present invention, the positioning portion provided on the flange portion and the engaging portion provided on the holding member that engages with the collar portion may have any shape or position as long as they engage with each other. . Also, the gap that occurs in the radial direction of the lens when the plastic lens member PL is held by the first and second holding members is such that the stress does not adversely affect the lens surface or the lens thickness due to thermal expansion or contraction. The gap shape and the gap may be set arbitrarily.

The present invention constitutes an optical apparatus in which an image is formed on a predetermined surface by using a taking lens in which the lens holding device in each of the above embodiments is held in a lens barrel.

[0024]

According to the present invention, by setting each element as described above, the lens can be accurately placed in the lens barrel (in the lens unit) in the optical axis direction and in the direction orthogonal to the optical axis (radial direction). , Can be easily positioned and assembled,
Further, it is possible to achieve a lens holding device and an optical device using the same, which does not impair the optical performance even when the environmental temperature changes.

In addition, according to the lens holding device of the present invention, (a1) the lens can be easily assembled while maintaining the optical performance while preventing the lens from being deformed due to the influence of expansion or contraction due to the temperature change of the lens. (A2) The eccentricity of the lens due to the influence of the expansion or contraction of the lens can be prevented. (A3) It is possible to prevent erroneous insertion of the front and back sides of the lens in the optical axis direction. And the like can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a first embodiment of the present invention.

FIG. 2 is a side view of a main part of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of assembly in the first embodiment of the present invention.

FIG. 4 is an explanatory diagram at the end of assembly according to the first embodiment of the present invention.

FIG. 5 is a schematic view of the essential portions of Embodiment 2 of the present invention.

FIG. 6 is a side view of a main part of the second embodiment of the present invention.

FIG. 7 is a schematic view of the essential portions of Embodiment 3 of the present invention.

FIG. 8 is a side view of the essential portions of Embodiment 3 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic lens 2 Collar part 3,12,13-15 Positioning part 4 1st holding member 5 2nd holding member 6-11,16-18 Engagement part

Claims (6)

[Claims] 1. An engagement for engaging a lens member having a flange portion for positioning in the optical axis direction on a peripheral portion of the lens and a positioning portion for radially positioning the lens on the collar portion, for engaging with the positioning portion. When held by a lens holding member having a section, the lens holding member is divided into at least two holding members by a cross section substantially parallel to the optical axis, and the positioning section is positioned near the cross section. A lens holding device characterized in that 2. The lens holding device according to claim 1, wherein the positioning portion and the engaging portion are engaged with each other in a relationship of a convex portion and a concave portion. 3. The positioning part is provided on at least two positions on a straight line including the center of the lens, with the center sandwiched therebetween, and radial distances from the center being substantially equal to each other. Or the lens holding device of 2. 4. The lens holding device according to claim 1, wherein a plurality of the positioning portions are provided, and the plurality of positioning portions are provided so as to deviate from point symmetry in the cross section. . 5. The lens holding device according to claim 1, wherein the lens is a plastic lens. 6. An optical device, wherein an image is formed on a predetermined surface by using a taking lens that houses the lens holding device according to claim 1. Description: